Low-pressure high-efficiency aqua ammonia absorption heat pump system  for BCHP residential use

ABSTRACT

A system of a low-pressure ammonia-water absorption chiller/heat pump combined with a thermal mass as a source of liquid coolant. The low-pressure ammonia-water absorption chiller/heat pump has a ratio of generator pressure to absorber pressure which is preferably not more than 2:1, and may include a condensate sub-cooler heat exchanger with a separate coolant supply. The thermal mass may be a swimming pool, a geothermal system, or a cooling tower, for example. Combined with an electrical power production device such as photovoltaic solar collector panels, or a fuel cell; the combined system produces residential electrical power generation along with residential space heating and cooling, thereby providing a residential BCHP (Building cooling, heating, and power) system having a very low carbon footprint and a high operating efficiency, such as measured by heat pump COP (Coefficient of Performance).

FIELD OF THE DISCLOSED INVENTIONS

The inventions disclosed herein pertain generally to a low-pressure high efficiency ammonia-water absorption heat pump system for BCHP (building cooling, heating & power) residential use, combined with a source of liquid coolant, and preferably in combination with a residential electrical power production system.

More particularly, the inventions disclosed herein pertain to a system of a low-pressure ammonia-water absorption chiller/heat pump combined with a source of liquid coolant which may be a thermal mass, such as a swimming pool, a geothermal system, or a cooling tower; in which the primary power source may be either passive solar collector panels, or preferably, a electrical power production device such as photovoltaic solar collector panels, or a fuel cell; thus combining residential electrical power generation systems and equipment with residential heating and cooling, thereby providing a residential BCHP system having a substantially zero carbon footprint and a high operating efficiency, such as measured by heat pump COP (Coefficient of Performance).

BACKGROUND

So-called BCHP systems based on photovoltaic solar systems or fuel cells for generation of electrical power are of increasing interest as a way of reducing energy costs and, further as a method of reducing the carbon footprint. The photovoltaic solar systems are typically based on solar collectors which have silicon-based semiconductor active layers. However, even high efficiency collector panels convert only 10-25% of the input (solar) energy to electrical energy, and fuel cells are typically limited to about 35% conversion of the input energy to electrical power. Thus, the remainder must be dissipated thermally in order to maintain equilibrium. This condition, then, requires that a powerful heat sink (i.e. a source of cooling) must be a part of any effective BCHP system. A further consideration in accomplishing a BCHP system is the desirability of using excess thermal energy from residential electrical power generation for residential space heating/cooling.

Thus, an effective single family residential BCHP system must include three major sub-systems: an electrical power generation sub-system, a building heating & cooling sub-system, and a heat storage/heat dissipation sub-system. Examples of these sub-systems exist separately, however as currently structured the existing sub-systems have major deficiencies in terms of sub-system inter-compatibility. As a consequence, there has been little market penetration by single family residential BCHP systems.

In terms of power generation sub-systems, photovoltaic electrical generation systems commonly have glazed collector panels, using glass either for transparent, non-reflective front sheets, and/or as substrates for the highest efficiency photovoltaic semiconductors. Such glazed collector panels are rigid, relatively delicate, and heavy due to the glass panels. As a result, although these systems have high solar energy-to-electrical energy conversion efficiencies, they have high purchase cost and also have especially high installation costs. Further, the added weight is often not conducive for structurally non-reinforced rooftop installation in home installations.

Another type of residential solar energy systems, photovoltaic thermal hybrids, commonly referred to as Hybrid PV/T systems, are solar radiation absorbing systems which combine two different methods of energy capture: photovoltaic which converts typically 15-25% of solar radiation into electricity, and thermal which captures and utilizes the remaining solar energy mainly for heating purposes. Since photovoltaic collector cells typically suffer from a drop in efficiency associated with a rise in operating temperature due to increased electrical resistance, a hybrid system has the additional benefit that it mitigates this problem; heat is carried away by the thermal part of the system keeping temperatures lower and consequently maintaining a high conversion efficiency. The thermal portion of hybrid solar heating systems are generally composed of solar thermal collectors attached to the photovoltaic panels, and a fluid system to move the heat from the collector to its point of usage. The fluid system typically uses electricity for pumping the coolant, and may have a reservoir or tank for heat storage and subsequent use.

A conventional photovoltaic hybrid design uses metallic coolant pipes attached to the back of the semiconductor photovoltaic collector. Coolant, such as water from mains, which is normally under 68° F. year round, exchanges heat with the PV collector as it runs along its back and heats up. The solar hot water is then siphoned or pumped to a container from which it can be used for various purposes. In many climates, a solar heating system can provide up to 85% of domestic hot water energy. In many northern European countries, combined hot water and space heating systems (solar combi-systems) are used to provide 15 to 25% of home heating energy. These uses, however, generally require the medium temperature solar hot water (typically above 110° F.) produced by concentrating solar thermal systems. In these systems the thermal collectors typically have glass panels with one of various types of lens effect to concentrate the solar energy at the collector. Overall, these systems are not well suited to heating swimming pools because the solar water temperature produced is too hot for swimming pools, the collectors are more expensive than low temperature collectors, and the greater weight of the collectors is not conducive to low-cost non-reinforced rooftop residential installation.

Among pumped solar heating systems, there is an important distinction to be made regarding the sustainability of the design of the system. This relates to what source of energy powers the pump and its controls. A type of pumped solar thermal systems which use mains electricity to pump the fluid through the panels are called low carbon solar because the pumping electrical need reduces the carbon savings of the solar by about 20%. However, zero-carbon pumped solar thermal systems use solar electricity which is generated onsite using photovoltaics to pump the fluid and to operate its control electronics. This represents the zero-carbon operational footprint which is becoming an important design goal for alternative energy systems.

Power generation sub-systems based on fuel cells also have similar concerns in terms of high thermal loads to be dissipated, and the effect of pumping requirements on the carbon footprint.

Another difficulty arises in using the excess thermal energy from residential electrical power generation for residential space heating/cooling. Heat pumps/air conditioners of a residential scale conventionally are of the vapor compression type that requires large amounts of electrical power for the compressors, substantially reducing the net electrical power production. From this perspective, absorption heat pumps which can use the excess thermal energy and have dramatically lower electrical requirements, could be more effective paired with electrical power generation. However, the most efficient and widely used absorption heat pumps are lithium-bromide based and are only made in very large capacities unsuited to residential scale.

Recently much work has been done on developing the ammonia-water cycle, which appears to be better suited to smaller scale applications, but has shown lower operating efficiencies, as measured for example by coefficient of performance (C.O.P.), especially in the cooling mode. Operating efficiencies of ammonia-water heat pumps are substantially improved by the use of a Generator-Absorber heat eXchanger (GAX) cycle. Examples of known ammonia-water heat pump devices, including GAX cycle devices and their operation are described in U.S. Pat. Nos. 5,782,097; 5,857,355; and Herbold, et al, “Absorption Chillers and Heat Pumps”, CRC Press, 1996; the contents of which are, respectively, incorporated herein by reference. However, even with the GAX cycle, conventional ammonia-water heat pump efficiencies are still significantly lower than the efficiencies of vapor-compression heat pumps, and are also lower than Lithium Bromide absorption heat pumps.

In practice, the performance efficiency of a GAX cycle is substantially limited by the portion of the required heat input to the generator which can be transferred from the absorber to the generator by means of the GAX. As illustrated in FIG. 1 of a state diagram for typical prior art ammonia-water absorption heat pump, where point A is the condenser and point B is the evaporator, the absorber extends from point C to point F, the generator extends from point D to point E, and the useable GAX heat transfer is represented by oblique arrows. A conventional prior art single-stage ammonia-water absorption heat pump typically operates in a temperature range between 30° F. to 400° F., with a generator-to-absorber pressure ratio of from about 3.0 to about 5.0 for example. Thus in a typical prior art ammonia-water absorption heat pump cycle with a GAX, the GAX heat transfer is limited to about 50% of the total required heat input to the generator and the remaining 50% must be made up by an external heat source of high temperature energy. This results in a typical prior art ammonia-water GAX absorption cooling cycle COP (Coefficient of Performance) of about 0.7 to about 1.1.

In contrast, the cooling COP of a conventional (electric) vapor-compression heat pump is often in the range of about 3 to 4. While the per-unit energy cost of natural gas for the ammonia-water absorption heat pump is much less expensive than the electrical cost for the vapor-compression, the substantial difference in COP is a significant barrier to wider use of ammonia-water absorption heat pumps.

Thus, improvements on the ammonia-water absorption heat pump cycle are needed to provide an effective combination with residential electrical power generation.

Relative to cooling sub-systems on a residential basis, swimming pools are one of the systems that could be considered as having the potential to store and/or dissipate large amounts of heat. However, conventional swimming pools systems are not very compatible with existing sub-systems for power generation and building heating & cooling, as described above.

Systems for supplemental heating of swimming pool water are one widespread method of extending the swimming season in the early spring and late fall. Previous systems, however, have been generally based on natural gas or propane heaters, or electrically driven heat pump systems, all of which have substantial operating expenses in terms of energy costs for direct heating of the water, as well as, energy cost for pumping. Thus, these previous systems have had high, or even very high, carbon footprints.

A popular method of reducing the swimming pool heating energy cost, and the carbon footprint, is by using supplemental solar heating systems. Conventionally, such systems have roof-mounted, low temperature, thermal solar collectors piped to a pumping/filtration/auxiliary heating system and electrical controls with thermostatic sensors. An important constraint is that, in the vast majority of home swimming pool systems, the solar collectors must be installed on the unreinforced existing roof of the residence due to space and esthetic considerations. Although feasible, the cost of glazed collector systems, and the potential cost of reinforcing an existing roof structure to support them is generally not attractive for swimming pool systems. Even without roof reinforcement, these solar systems are significantly more expensive to purchase and install compared to natural gas or heat pump systems.

In addition, such solar thermal systems for swimming pools have significant electrical operating expenses, for the required extended operation of pumps. All of these factors have tended to limit their wide-spread use. When combined with the conventional natural gas fired furnace and vapor-compression air conditioner, the total system has a very substantial operating energy cost and a significant carbon footprint.

A further barrier to an effective BCHP system is the conflicting operational needs for the different sub-systems of a potential BCHP system. In addition to high purchase cost, the operating requirements of conventional photovoltaic solar power generation systems conflict with the operation of conventional swimming pool solar heating systems. Conventional solar swimming pool heating systems regulate pool water temperature by manually, or automatically, shutting off water circulation to the solar panels once a desired pool temperature is achieved. However, this control method would greatly interfere with effective photovoltaic power generation which requires continuous operation during periods of high incident solar energy. Loss of cooling would result in elevated operating temperatures with degraded photovoltaic power generation. Further, such periodic system shutdowns make ineffective combination with residential space heating/cooling and domestic hot water heating requirements, where continuous availability of operation is a necessity.

In consequence of the above considerations, photovoltaic power generation is not broadly included in residential solar heating systems, even though the value of photovoltaic power generation, and the near zero-carbon footprint that it offers would otherwise be highly attractive. Thus there exists a significant need for improvement in existing solar energy systems.

With the above considerations in mind, one objective of the present invention is to improve the effectiveness of GAX heat exchange in an ammonia-water absorption heat pump. A second objective of the present invention is an effective BCHP system for single family residences incorporating efficient photovoltaic or fuel cell power generation, while preserving many of the advantages of a conventional swimming pool heating system. Another objective of the present invention is a photovoltaic or fuel cell powered swimming pool solar heating system with a temperature control method and device which allows continuous operation of the power generation while maintaining suitable water temperatures for residential swimming pool systems. A further objective of the present invention is an effective combination of residential space heating/cooling and domestic hot water heating with residential electrical power generation.

SUMMARY OF DISCLOSED EMBODIMENTS OF THE INVENTIONS

The disclosed inventions are herein described in terms of illustrative non-limiting embodiments. In a series of embodiments of the disclosed inventions, a low pressure ammonia-water absorption chiller/heat pump system for BCHP residential applications comprises a low pressure ammonia-water absorption chiller/heat pump in thermal communication with a thermal mass (e.g. a swimming pool or a geothermal system) for storing and dissipating thermal energy, and a primary power source (e.g. a solar system or fuel cell) in thermal communication with the thermal mass. In exemplary embodiments, the low pressure ammonia-water absorption chiller/heat pump includes the basic absorption heat pump components of a generator, an absorber, a condenser, and an evaporator; together with a GAX (generator-absorber exchanger) cycle, and pump & valve components necessary to the function of the chiller/heat pump.

In one exemplary embodiment, the low-pressure ammonia-water absorption chiller/heat pump system includes a plenum-mounted indoor heat exchanger in direct, or indirect, thermal communication with a first thermo-fluid liquid liquid and with an air flow from a residential living space, and a thermal mass heat exchanger in fluid communication with said first thermo-fluid liquid which is in thermal communication with the thermal mass. The primary condenser is in fluid communication and thermal communication, direct or indirect, with the first thermo-fluid liquid. The generator operates at a preselected generator internal pressure consistent with the condenser, and includes a generator heat source which provides the necessary high temperature heat to supplement the GAX heat transfer from the absorber. The absorber is cooled by a flow of first thermo-fluid liquid from the thermal mass, and operates at a preselected absorber internal pressure consistent with the evaporator temperature. The performance of the absorption heat pump is greatly increased due to substantially improved effectiveness of the GAX heat transfer due to a low-pressure ratio between the low-pressure generator and the absorber.

In a further embodiment, the first thermo-fluid liquid (e.g. a coolant) flows out of the absorber and is directed to a rectifier pre-cooler heat exchanger, providing preheat for a Domestic Hot Water (DHW) supply to a living space, and is then directed to a rectifier, or a reflux coil, in the generator. In an embodiment for cooling, a flow of first thermo-fluid liquid flow to the absorber is configured in parallel to a flow of first thermo-fluid liquid to the condenser; flowing in sequence from the absorber to the DHW exchanger, to the reflux coil and from the reflux coil to the absorber, the first thermo-fluid liquid coolant flow is then returned to the thermal mass. In an embodiment for heating, a flow of first thermo-fluid liquid to the absorber is configured in series with the condenser; going in sequence to the absorber, the DHW exchanger, and the reflux coil, from the absorber the flow of first thermo-fluid liquid is directed to the condenser before being returned to the thermal mass, thereby partially compensating for seasonably lower temperatures in the thermal mass.

In several embodiments, the low-pressure ammonia-water absorption chiller/heat pump system includes a control module which provides heating and cooling configuration changes to accommodate heating and cooling differences due to daytime vs. night-time, and seasonal requirements. Certain embodiments of the low-pressure ammonia-water absorption chiller/heat pump system include a refrigerant reversing valve and an air coil coolant reversing valve to facilitate the conversion from air conditioning to heat pump operation. In several preferred embodiments, the low-pressure ammonia-water absorption chiller/heat pump system includes a two-step condenser system having a primary condenser cooled by the first thermo-fluid liquid and a condensate sub-cooler cooled by a sub-cooler coolant source.

Additional embodiments may include a primary power source which produces electrical power for local use, and possibly for connection to a power grid. The primary power source may be photovoltaic solar panels, a fuel cell, or a fuel cell with passive solar panels for nighttime cooling.

The photovoltaic solar panels include a elongate lumened substrate, with a plurality of lumens, having a photovoltaic semiconductor layer bonded to an upper surface. In one preferred embodiment, the photovoltaic semiconductor layer is a CIGS semiconductor structure with a metal foil base, which serves as a back contact, with an absorber layer of Cu(In,Ga)Se₂ doped p-type deposited on an upper surface. A buffer layer comprising a lower layer of CdS and an upper layer of ZnO is deposited on an upper surface of the absorber layer. A transparent layer of ZnO:Al doped n-type is deposited on an upper surface of the buffer layer, and serves as the front contact. The photovoltaic semiconductor layer is susceptible to moisture and requires encapsulation.

Other and further embodiments, aspects and features of the disclosed embodiments will become apparent to those skilled in the art in view of the accompanying figures and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of embodiments of the disclosed inventions, in which similar elements are referred to by common reference numerals, and in which:

FIG. 1 (Prior art) is an illustrative plot of the thermodynamic states at key points (denoted by letters) in a typical ammonia-water absorption chiller/heat pump of the prior art.

FIG. 2 is an illustrative plot of the thermodynamic states at key points (denoted by letters) in an ammonia-water absorption chiller/heat pump of one embodiment of the present invention.

FIG. 3 shows a schematic diagram of two different embodiments of an ammonia-water absorption chiller/heat pump system of the present invention, depicted in an air cooling mode.

FIGS. 4 a and 4 b depict schematic diagrams of embodiments of an ammonia-water absorption chiller/heat pump system of the present invention, depicted in an air cooling mode and illustrating a daytime air cooling configuration and a nighttime thermal mass cooling configuration, respectively.

FIGS. 5 a and 5 b depict embodiments of an ammonia-water absorption chiller/heat pump system of the present invention, depicted in an air heating mode and illustrating a daytime air heating configuration and a nighttime air heating configuration, respectively.

FIG. 6 is a schematic diagram of an alternate embodiment of an ammonia-water absorption chiller/heat pump system of the present invention, depicted in a air cooling mode, in which the sub-cooler coolant source is a water main and the water is subsequently reused for domestic water needs.

FIG. 7 a depicts a cross-sectional view of one embodiment of a lumened polymeric substrate that may be used in combination with any of the ammonia-water absorption chiller/heat pump system embodiments of the present invention.

FIG. 7 b illustrates a magnified cross-sectional view showing details of the photovoltaic layer sub-structure of one embodiment of a metal foil with a photovoltaic layer that may be used in solar panel embodiments of the present invention.

DETAILED DESCRIPTION

Embodiments of the inventions disclosed and described herein are directed to a system of a absorption heat pump, and a means of residential electrical power generation and their use in circulating coolant systems, in particular but not limited to residential heating/cooling and solar heating of residential BCHP systems. By way of non-limiting examples, embodiments of the present inventions include a low pressure ammonia-water absorption chiller/heat pump 10 for use with a thermal mass 20, (e.g. a swimming pool or a geothermal system), and with a primary power source 30 (e.g. passive solar collector panels, photovoltaic solar collector panels, or fuel cells), combining residential electrical power generation systems and their use with circulating coolant systems having thermal mass, in particular to but not limited to residential heating and cooling and/or solar heating of swimming pools.

The following detailed description is directed to exemplary embodiments of the present inventions, particularly embodiments used for residential space heating and cooling in combination with residential electrical power generation. However, such embodiments are disclosed and described by way of illustration, and not limitation, and other and different heat pump and system embodiments in other configurations are also contemplated herein.

For purposes of illustration, and with reference generally to exemplary embodiments of the disclosed inventions, FIG. 2 illustrates the thermodynamic states at key points (denoted by letters) in an ammonia-water absorption chiller/heat pump 10 of one embodiment of the present invention. The condenser (A) and the generator (D to E) operate at a shared internal generator pressure over an illustrated temperature range of about 80° F. to 345° F., and the evaporator (B) and the absorber (C to F) operate at a shared internal absorber pressure over an illustrated temperature range of about 55° F. to 315° F. The GAX heat flow from the absorber to the generator is illustrated by arrows and takes place over the temperature range for which the absorber internal temperatures are higher than the temperatures at corresponding points in the generator.

The illustrated relatively low internal generator pressure, and the as illustrated relatively low ratio of the generator internal pressure to the absorber internal pressure are important characteristics of the disclosed inventions.

For purposes of further illustration, and with reference generally to exemplary embodiments of the disclosed inventions, FIG. 3 illustrates two exemplary embodiments of a low pressure ammonia-water absorption chiller/heat pump system 10 combining a low pressure ammonia-water absorption chiller/heat pump 40 with a thermal mass 20, FIG. 3 a, and with a primary power source 30, FIG. 3 b, in residential applications of heating/cooling systems and their use with circulating coolant systems.

In various exemplary embodiments, a low pressure ammonia-water absorption chiller/heat pump 40 of the present inventions has the basic components of a GAX ammonia-water absorption heat pump, including: a generator 42 operating at a pre-selected generator pressure, an absorber 44 operating at a pre-selected absorber pressure, a restrictor valve providing the necessary pressure drop to the absorber 44, an evaporator, a condenser, a generator external heat source, e. g. a natural gas burner (not illustrated), and a GAX heat exchanger 47 fed by a GAX pump 46. The generator 42, the absorber 44, a thermal mass heat exchanger 51, and an air coil 62, which may serve as the condenser and the evaporator respectively, are cooled by a circulating coolant (i.e. a first thermo-fluid liquid that for the purposes of this disclosure may be water from a swimming pool) which is in thermal communication with a thermal mass 20.

In one exemplary embodiment of the present invention illustrated in FIG. 3 a for use as a swimming pool heater, the thermal mass heat exchanger 51 serves as a condenser, and the air coil 62 serves as an evaporator; by which heat may be removed from ambient air and used for heating the thermal mass 20, for example, a swimming pool. An evaporator pre-cooler 54 provides heat exchange between the evaporator feed stream and outlet stream thereby increasing the effectiveness of the evaporator. The air coil 62 acting as the evaporator may be fed by a one-way expansion valve 63 having a check valve bypass acting to allow low pressure drop flow in a reverse direction, and an air coil coolant reversing valve 65 which reverses the direction of flow through the air coil 62. This allows the heat exchange to be reversed such that some excess heat from the swimming pool water may be dissipated to the ambient air. The ambient air may be outdoor ambient air. A first thermo-fluid liquid circulation pump 32 provides flow of first thermo-fluid liquid to various components.

In another exemplary embodiment illustrated in FIG. 3 b, an ambient air heat exchanger 60, is a refrigerant-to-air heat exchanger and has an air coil 62 mounted in an indoor air plenum 64, providing thermal exchange between the refrigerant (e.g. ammonia) and room air from a residential living space. Due to the irritant properties of ammonia, the refrigerant side is isolated from the residential living space by use of an isolation heat exchanger 56 providing an intermediate coolant loop between the ammonia refrigerant and the air coil 62. The intermediate coolant may be the first thermo-fluid liquid, or another inert coolant fluid. The ambient air heat exchanger 60 serves as the evaporator when the system is operating in a chiller mode (i.e. transferring heat from the ambient air to a thermal mass 20 by means of the first thermo-fluid liquid), but serving as the condenser when the system is operating as a heat pump in a heating mode (i.e. transferring heat to the ambient air from the thermal mass). A thermal mass heat exchanger 51, which is a refrigerant-to-liquid heat exchanger and in some embodiments is an outdoor heat exchanger, provides thermal exchange between the refrigerant and the thermal mass 20 by the medium of the first thermo-fluid liquid (e.g. swimming pool water when the thermal mass is a swimming pool); serving as the condenser when the system is operating in a chiller mode, and serving as the evaporator when the system is operating as a heat pump in a heating mode.

A refrigerant reversing valve 50 may be included to reverse the flow direction of refrigerant thereby interchanging the position of the condenser and the evaporator. The thermal mass heat exchanger 51 and the ambient air heat exchanger 60, acting in the alternative as the evaporator, may be fed by a one-way expansion valve 63 providing a high pressure drop in the direction of the evaporator, and having a check valve bypass acting to allow a low-pressure drop flow in the reverse direction. A primary power source 30 is a source of heat which is absorbed by a flow of first thermo-fluid liquid controlled by an air coil coolant reversing valve 65, which reverses the flow direction of first thermo-fluid liquid circulation in the isolation heat exchanger 56 to change from a mode of cooling the ambient air to a mode of heating the ambient air.

The absorber 44 is cooled by a flow of first thermo-fluid liquid circulating through an absorber heat exchanger 43 located in a low temperature region of the absorber 44, the first thermo-fluid liquid flow may then be cooled by a rectifier precooler heat exchanger 92 before flowing to the rectifier 41 located in a high temperature region of the generator 42. In a series of embodiments, the rectifier precooler heat exchanger 92 is cooled by a flow of mains water 91, which is subsequently directed as preheated water to an infeed of a Domestic Hot Water (DHW) heater 90 thereby using waste heat to reduce the prime energy consumption of the DHW heater 90.

The low pressure ammonia-water absorption chiller/heat pump 40 of the present disclosure has a low pressure generator 42, which for this disclosure is defined as a generator having an internal operating pressure of about 200 psia or less, and preferably in a range of 110-180 psia. In one series of exemplary embodiments of the instant invention, as illustrated in FIG. 2, the overall design temperature range of the disclosed invention is about 50° F. to 350° F., which is similar to the design temperature range of the prior art of about 40° F. to 350° F. However, the low pressure generator 42 restricts the pressure range of the low pressure ammonia-water absorption chiller/heat pump 40 of the present disclosure to a narrow operating window, as illustrated in FIG. 2, which increases the effectiveness of the GAX heat transfer.

It is convenient to express this operating pressure range as a ratio of the generator pressure to the absorber pressure. Thus, for the embodiment of the present invention illustrated in FIG. 2, the pressure ratio is about 1.5:1, as compared to the pressure ratio of typically about 4:1 for the prior art as illustrated in FIG. 1. As can be seen by comparison of FIGS. 1 & 2, the low pressure ratio of the low pressure ammonia-water absorption chiller/heat pump 40 of the present disclosure results in a greatly expanded temperature range over which the GAX can effectively transfer heat from the absorber 44 to the low pressure generator 42. As a result of the increase in the effectiveness of the GAX, the overall coefficient of performance (COP) of the low pressure ammonia-water absorption chiller/heat pump 40 of the present disclosure is increased to as much as 2.0 or more, versus typical COP values of about 0.7-1.0 for the prior art ammonia-water absorption heat pumps and about 1.7 for lithium bromide absorption heat pumps.

It should be noted that other embodiments of the herein disclosed invention may have pressure ratios up to 2:1; and still other embodiments of the present disclosure may have low pressure generators with pressure ratios up to 2.5:1, or even up to 2.8:1, depending on the particular embodiment, but preferably the pressure ratio is less than 2:1 in embodiments used for residential space cooling applications.

As noted above, the low pressure ammonia-water absorption chiller/heat pump 40 of several preferred embodiments of the present disclosure is integrally coupled (directly plumbed, i.e. “hard-wired”) to the thermal mass 20 via the thermal mass heat exchanger 51 using the first thermo-fluid liquid as a heat transfer medium. For the purpose of this disclosure, the thermal mass 20 is defined as a body having offering a capacity for storage and/or dissipation of thermal energy equivalent to the net daily thermal energy input to (and produced within) the low pressure ammonia-water absorption chiller/heat pump 40 of the present disclosure after accounting for heat dissipation. It will be understood that the thermal dissipation associated with the thermal mass 20 is to be sufficient compared to the total thermal load input to the low pressure ammonia-water absorption chiller/heat pump system 10 so that the system can maintain equilibrium on a daily and seasonal basis; and that the thermal storage capacity of the thermal mass 20 is to be sufficient to accommodate short-term differences between the total thermal load input rate and the thermal dissipation rate so as to maintain the system in equilibrium on a daily and seasonal basis. The relative proportions of storage and dissipation may vary significantly among different embodiments; and in general terms, the higher the dissipation rate available, the lower the thermal storage capacity that will be required. Among illustrative and non-limiting examples of embodiments of the thermal mass 20 of the present disclosure are the body of water in a swimming pool, a geothermal system, and a cooling tower/evaporative cooler; however other embodiments meeting the above criteria for the thermal mass 20 are also envisioned and contemplated herein.

The thermal mass 20 of the present invention incorporates a heat sink to accomplish the necessary thermal storage and heat dissipation. This heat sink may take different forms depending on the specific embodiment of the thermal mass 20. By way of illustrative and non-limiting examples, for embodiments in which the thermal mass 20 is a geothermal system, the heat sink may be indirect by heat conduction into the geothermal body; whereas in embodiments in which the thermal mass 20 is a cooling tower the heat sink may be convective and/or evaporative cooling by ambient air; and for embodiments in which the thermal mass 20 is swimming pool water connected to a solar panel that is the primary power source 30, the heat sink may be night-sky cooling by nighttime recirculation of water directly from the thermal mass 20 to the solar panel.

By way of illustrative and non-limiting examples, in one preferred embodiment of the instant inventions, the cooling tower may be an evaporative condenser, and the ambient air coil 62 may be plenum mounted for use in residential living space heating and cooling as a replacement for a conventional vapor compression heat pump.

In another exemplary embodiment, the air coil 62 is exterior and the low pressure ammonia-water absorption heat pump 10 may be used for heating the water of a swimming pool through transferring heat from the ambient air heat exchanger mounted in outside ambient air to the thermal mass heat exchanger circulating swimming pool water, which acts as the first thermo-fluid liquid. However, other embodiments of the thermal mass 20 and heat sink are also envisioned and contemplated herein.

Although several embodiments of the instant inventions are based on the core elements of a low pressure ammonia-water absorption chiller/heat pump 40 and a thermal mass 20, a various other embodiments also include a primary power source 30. By way of definition for the purposes of this disclosure, in certain embodiments, the primary power source 30 may be a purely passive device (i.e. producing only sensible heat energy); however, in various other embodiments especially of the BCHP type, the primary power source 30 may also produce electrical power for connection to an electrical power grid (not illustrated). By way of illustrative and non-limiting examples of embodiments of the present disclosure, are embodiments in which the primary power source 30 may be selected from a group consisting of at least one passive solar panel, at least one photovoltaic solar panel, at least one fuel cell, and a combination of at least one passive solar panel with at least one fuel cell. However other embodiments of the primary power source 30 are also envisioned and contemplated herein.

As noted above, the low pressure ammonia-water absorption chiller/heat pump 40 requires a external source of generator heat (not illustrated) capable of delivering that generator heat at temperatures in the 300° F.-400° F. range. A preferred external source of generator heat may vary with the various embodiments of the primary power source 30. For example, if the primary power source 30 is a set of lower temperature solar panels, a preferred external source of generator heat may be direct, or indirect, combustion heating of the high temperature section of the low-pressure generator 42. The combustion fuel might be a gas (e.g. natural gas or propane), or a liquid hydrocarbon (e.g. fuel oil or gasoline). However, if the primary power source 30 has a sufficiently high operating temperature, such as a fuel cell for example, a preferred external source of generator heat may be direct, or indirect, heating of the high temperature section of the low-pressure generator 42 by a suitable heat transfer fluid circulating through, and cooling, the primary power source 30 itself.

In various embodiments, a pump and valve system serves to provide fluid communication, and/or thermal communication, by means of the first thermo-fluid liquid, between said thermal mass 20, said low pressure ammonia-water absorption chiller/heat pump 40, and said primary power source 30. This system of pump(s) and valves is interconnected with a control module 25 allowing flexibility for manual or automatic changes in configuration for thermal load balancing as needed on a diurnal and seasonal basis depending on heating and cooling needs, and on environmental conditions. One exemplary embodiment of a pump and valve system is illustrated in FIG. 4, where closed valves are shown shaded (such as valve 74, for example), and open valves are shown without shading.

A further exemplary embodiments of the pump & valve system include an air coil coolant reversing valve 66 which provides a heat dissipation configuration of said pump & valve system, said primary power source 30, and said thermal mass 20 whereby excess thermal energy may be dissipated to an external environment during a time period of non-production of power or heat by said primary power source 30. The exact nature of the heat dissipation configuration depends on the nature of the particular primary power source 30 and the thermal mass 20 employed. One exemplary embodiment of the heat dissipation configuration, when the primary power source is a solar panel(s), is night-sky cooling wherein excess thermal heat is radiated into space from the solar panel(s). Another exemplary embodiment of a heat dissipation configuration, when a geothermal system is the thermal mass 20, is simply recirculation the first thermo-fluid liquid back to the geo-thermal mass. A further exemplary embodiment of a heat dissipation configuration, when a cooling tower/evaporative cooler is the thermal mass, is night-time circulation of coolant to provide evaporative cooling of the first thermo-fluid liquid. However, other embodiments of the primary power source 30 with a heat dissipation configuration having a coolant reversing valve 66 providing heat dissipation to an external environment are also envisioned and contemplated herein.

In an exemplary embodiment for BCHP applications, as illustrated in FIG. 3, the ambient air heat exchanger 60 is a plenum-mounted indoor heat exchanger in thermal communication with the ammonia refrigerant and with an air flow from a residential living space, and the thermal mass heat exchanger 51 is an outdoor heat exchanger 51 in thermal communication with the ammonia refrigerant and in fluid communication with the thermal mass 20. In various embodiments, the low pressure ammonia-water absorption chiller/heat pump system 10 may transfer heat from a residential living space to the thermal mass (a cooling mode), or from the thermal mass to the residential living space (a heating mode).

It will be understood that due to the irritant properties of ammonia, the ammonia is generally kept separated from the residential living space. Therefore, when the ambient air heat exchanger 60 has an air coil 62 mounted in an indoor air plenum 64 (i.e. inside of, or in contact with, air from a residential living space), the ammonia refrigerant side of the ambient air heat exchanger 60 is kept exterior to the residential living space, and the air therein, by an isolation heat exchanger 56, as illustrated in FIG. 3 b, using a second thermo-fluid (i.e. a heat exchange medium suitable for use interior of a residential living space). In certain embodiments, the first thermo-fluid liquid may be used as the second thermo-fluid (i.e. in the intermediate heat exchanger loop 61) if freezing and other considerations are addressed.

It will also be understood by practitioners of the art that due to the corrosive properties of ammonia, particularly with respect to copper, metals such as iron, nickel, 316 stainless steel, titanium, Inconel, or zirconium are generally preferred for piping, and heat exchange surfaces, etc. in contact with ammonia. In certain circumstances, aluminum may also be used.

Other embodiments of the herein disclosed inventions include a refrigerant reversing valve 50 which allows the low pressure ammonia-water absorption chiller/heat pump 40 to function as either a chiller or as a heat pump by reversing the direction of refrigerant flow between the ambient air heat exchanger 60 and the thermal mass heat exchanger 51, thereby changing from a cooling mode to a heating mode. A typical refrigerant reversing valve 50 may have many ports, although for purposes of brevity in the illustration only the most basic ports are shown in FIG. 3 b as planning for additional ports is within ordinary skill in the art. In changing from a air cooling mode to an air heating mode, or vice versa, the direction of flow in the evaporator pre-cooler 54 also needs to be modified by an appropriate combination of valves. One embodiment using the refrigerant reversing valve is illustrated in FIG. 3 b, where port pairs which are interconnected within the refrigerant reversing valve 50 are shown with the same labels.

Various embodiments, particularly directed to BCHP applications, may also include a control module 25 providing a diurnal and seasonal thermal load balancing system by which the low pressure absorption chiller/heat pump 40 and the pump & valve system are automatically reconfigured for daytime and nighttime and/or seasonally, selecting between an air heating mode and an air cooling mode depending on a user input and seasonal ambient conditions. Such embodiments are illustrated in FIGS. 4 and 5, for example, wherein the ambient air heat exchanger 60 is a plenum-mounted indoor heat exchanger in thermal communication with air from a residential living space, the thermal mass heat exchanger 51 is an outdoor heat exchanger, and a system for cooling the thermal mass 20 is in thermal communication with the thermal mass 20, by which a flow of said first thermo-fluid liquid is cooled thereby serving to maintain stable conditions in the thermal mass 20 through dissipation of excess thermal energy (e.g. by night-sky cooling with solar panels).

By way of non-limiting embodiments, the control module 25 may include an air cooling configuration, as illustrated in FIG. 4 a, in which a first flow 34 of first thermo-fluid liquid coolant to the thermal mass heat exchanger 51 is in parallel to a second flow 36 of first thermo-fluid liquid which provides cooling to the absorber 44; and an air heating configuration, as illustrated in FIG. 5 a, in which the flow of first thermo-fluid liquid to the thermal mass heat exchanger 51 is in series with the absorber 44 whereby the thermal mass heat exchanger 51 receives the flow of first thermo-fluid liquid preheated by the absorber 44. In the illustrated embodiment, this change in configuration may be effectuated by valves such as 31, 33, and 37, and provides more efficient cooling in an air cooling mode, and more heat available to the thermal mass heat exchanger 51 when serving as the evaporator in an air heating mode, thereby partially compensating for seasonably lower temperatures in the thermal mass 20.

In certain embodiments wherein the primary heat source 30 is at least one solar panel, the thermal mass cooling system includes a pre-selectable diurnal control of an automated nighttime recirculation of the first thermo-fluid liquid by the pump & valve system, which is in fluid communication with the thermal mass 20 and with the at least one solar panel, thereby providing nighttime cooling of said thermal mass 20. By way of other non-limiting embodiments, the control module 25 includes valving with an air cooling configuration which in the daytime provides a flow 35 of the first thermo-fluid liquid that goes in series: first to the ambient air heat exchanger 60, then to the primary power source 30, and thence back to a return 75 to the thermal mass 30, as illustrated in FIG. 4 a. However, at nighttime when cooling of the thermal mass 20 is needed, the air cooling configuration provides a flow 35 of the first thermo-fluid liquid that goes in parallel to both the primary power source 30 and the ambient air heat exchanger 60, and then from both back to a return 75 to the thermal mass 30, as illustrated in FIG. 4 b, whereby cooling of the thermal mass 20 is effected without interference with the cooling of the air in the plenum 64.

Another non-limiting embodiment illustrated in FIG. 4, has a Domestic Hot Water (DHW) preheating system having a rectifier precooler heat exchanger 92 which uses heat from the absorber 44 to pre-heat water from a mains water supply 91 for use as domestic hot water. The then-cooled first thermo-fluid liquid may also be directed to the generator reflux exchanger 41, or alternatively a rectifier, to remove water vapor from the ammonia vapor leaving the low pressure generator 42.

In several exemplary preferred embodiments, the low pressure ammonia-water absorption chiller/heat pump 40 has a two-step condenser system having a primary condenser 51 which receives a flow of refrigerant vapor from the low-pressure generator 42, and which is cooled by a flow of first thermo-fluid liquid; and a condensate sub-cooler 52 which receives refrigerant condensate from the primary condenser and which is cooled by condensate sub-cooler coolant from a condensate sub-cooler coolant source 74. The temperature of the condensate sub-cooler coolant is lower than the temperature of the first thermo-fluid liquid. Thus, when the first thermo-fluid liquid temperature is too high to accomplish a desired low-pressure operating condition in the condenser 51 and therefore in the low-pressure generator 42, the lower temperature of the condensate sub-cooler coolant will lower the internal pressure of the condenser 51 and therefore of the low-pressure generator 42. In one preferred embodiment, the primary condenser 51 is an evaporative condenser.

In certain preferred embodiments the thermal mass cooling system offers one or more options for the condensate sub-cooler coolant source 74. For example, when the thermal mass cooling system has one or more solar panels operating with night-sky cooling, the night-sky solar panels may be the condensate sub-cooler coolant source 74 option of choice as illustrated in FIG. 4 a; when the thermal mass cooling system is a geothermal system, the geothermal system itself may be the condensate sub-cooler coolant source 74 option of choice; when the thermal mass cooling system is a cooling tower, the tower may provide a condensate sub-cooler coolant source 74 of choice; and in all cases, these options for the condensate sub-cooler coolant source 74 may be supplemented, in whole or in part, by a mains water supply 75. This latter option is possible because the heat load on the condensate sub-cooler 52 is only a fraction of the total condenser heat load, often on the order of 15% or less. In the case of mains water, the water needed for the condensate sub-cooler 52 may be reused for other domestic needs such as hot and cold water, and make-up water to correct for evaporation from a swimming pool or a wet cooling tower, for examples. In certain embodiments, the mains water may be pre-cooled in a heat exchange passage of a combination evaporator pre-cooler 55 as illustrated in FIG. 6.

In a related exemplary embodiment, the condensate sub-cooler coolant source 74 includes a condensate sub-cooler coolant reservoir 71 that provides a reserve of condensate sub-cooler coolant to ensure a continuous supply of condensate sub-cooler coolant even when the condensate sub-cooler coolant source 74 is temporarily unable to keep up with demand. Generally the condensate sub-cooler coolant reservoir 71 is located upstream of the condensate sub-cooler 52 and is thermally insulated from the ambient environment. However, in other embodiments when the condensate sub-cooler coolant is to be reused for other domestic water needs, a non-insulated condensate sub-cooler coolant accumulation tank 76 may be located downstream of the condensate sub-cooler 52, as illustrated in FIG. 6.

Further, in certain preferred embodiments wherein the primary heat source 30 is a set of solar panels, at least one solar panel is a photovoltaic solar panel having an elongate planar lumened substrate 111, as illustrated in FIG. 7 a, with a plurality of longitudinal supply lumens 112 in fluid communication with the pumping and valve system. A photovoltaic semiconductor layer 110 is bonded on an upper surface of the lumened substrate and in thermal communication thereto. A first electrode and a second electrode are electrically connected to positive and negative poles of said photovoltaic semiconductor layer 110. A control module 25 is in electrical communication with the pumping and valve system and with the first and second electrodes, and preferably having a diurnally and seasonably automatically reconfiguring photovoltaic-thermal load balancing control system. Solar energy incident on the photovoltaic semiconductor layer 110 causes photovoltaic electrical power to be generated and available to an electrical circuit in electrical communication with said photovoltaic semiconductor layer 110. The unconverted solar energy is absorbed as excess thermal energy by a thermo-fluid circulating in the supply lumens. The photovoltaic-thermal load balancing control system, being in thermal communication with said thermal mass 20 and with said thermal fluid in said longitudinal supply lumens 112; and preferably having diurnal and seasonal preselected reconfigurations, provides stable operation of the photovoltaic semiconductor layer 110 at preselected temperatures at all times of day and in all seasons, directing the excess thermal energy into thermal heating and cooling for various residential uses, such as residential space heating and solar heating of a swimming pool.

In further preferred embodiments, a thin flexible sheet of metal foil 122 may be bonded to an upper surface of the lumened substrate 110; with a thin-film photovoltaic semiconductor layer 120 deposited on an upper surface of said metal foil 122. As illustrated in FIG. 7 b, the thin-film photovoltaic semiconductor layer 120 may have an electrically conductive upper (i.e. sunward) stratum 130 that is substantially transparent to selected solar radiation and a photovoltaic absorber stratum 124 in electrical and thermal communication with the metal foil 122. In at least one embodiment, the electrically conductive upper (i.e. sunward) stratum 130 includes metallic grids on or partially embedded in an upper surface to enhance electrical contact. The first electrode and the second electrode are electrically connected to the electrically conductive upper stratum and to the metal foil, respectively. The control module, electrically connected to said first electrode and said second electrode, includes an inverter in electrical communication with a residential electrical main (not illustrated).

The photovoltaic semiconductor layer 120 further has buffer stratum 126 & 128 atop said absorber stratum 124 and beneath said electrically conductive upper stratum 130, and an essentially waterproof encapsulant material encapsulating all exposed exterior surfaces of said photovoltaic semiconductor layer 122. In one embodiment, the lumened substrate is a somewhat flexible lumened polymeric substrate. In another embodiment, the absorber stratum 124 is a doped p-type CIGS semiconductor comprising (Cu(In, Ga)Se₂); the electrically conductive upper stratum 130 comprises a doped n-type ZnO:Al semiconductor; and a buffer stratum further comprises a ZnO stratum 128 atop a CdS stratum 126, with said buffer stratum 128 immediately below said electrically conductive ZnO:Al upper stratum 130. The lumened polymeric substrate may be a polyolefin polymer; the sheet of metal foil may be substantially Mo; the encapsulant material may comprise a fluoropolymer front sheet and an EPDM back sheet. The metal foil may be bonded to said lumened substrate by a hot melt adhesive comprising EPDM which may serve as the back sheet.

While certain exemplary embodiments have been described herein and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative and not restrictive of the inventive concepts and features, and that the inventions disclosed herein are not limited to the specific constructions and arrangements shown and described, as various further and other modifications may occur to those skilled in the art upon studying this disclosure. 

1. A low pressure ammonia-water absorption chiller/heat pump system for residential BCHP (building cooling, heating, and power) use with a thermal mass, comprising: a low pressure ammonia-water absorption chiller/heat pump having an absorber cooled by a first thermo-fluid liquid liquid and having a preselected, or pre-determined, absorber internal pressure consistent with said first thermo-fluid liquid temperature, a low pressure generator with a preselected, or pre-determined, generator internal pressure and having a generator external heat source, a generator-absorber heat exchanger (GAX) system, an ambient air heat exchanger which is a refrigerant-to-air heat exchanger having fluid communication with an ammonia refrigerant and being in thermal communication with a flow of ambient air, an thermal mass heat exchanger which is a refrigerant-to-liquid heat exchanger having fluid communication with said ammonia refrigerant and being in thermal communication with said first thermo-fluid liquid having said first thermo-fluid liquid temperature, and a thermal mass for storage and/or dissipation of thermal energy, said thermal mass being in thermal communication with said first thermo-fluid liquid; wherein said thermal mass heat exchanger serves as a condenser when operating in a cooling mode (i.e. transferring heat from said ambient air to said first thermo-fluid liquid), and serves as an evaporator when operating in a heating mode (i.e. transferring heat to said ambient air from said first thermo-fluid liquid); and wherein said ambient air heat exchanger serves as an evaporator when operating in said cooling mode, and serves as an condenser when operating in said heating mode; and further wherein said low pressure ammonia-water absorption chiller/heat pump has a ratio of an internal absolute pressure within said low pressure generator to an internal absolute pressure within said absorber equal to or less than 2.8:1.
 2. The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP (building cooling, heating, and power) use with a thermal mass as in claim 1, further comprising a primary power source in thermal communication with said ammonia-water absorption chiller/heat pump and with said thermal mass; a pump & valve system in fluid communication with said absorption heat pump, with said thermal mass, and with said primary power source; and a coolant reversing valve which provides a heat dissipation configuration of said pump & valve system, said primary power source, and said thermal mass whereby excess thermal energy may be dissipated to an external environment during a non-power producing time period.
 3. The ammonia-water absorption system for BCHP residential use with a thermal mass of claim 2, wherein said ambient air heat exchanger is a plenum-mounted indoor heat exchanger in thermal communication with an ammonia refrigerant and in thermal communication with an air flow from a residential living space, said air flow having a living space temperature, and said thermal mass heat exchanger is an outdoor heat exchanger in fluid communication with said ammonia refrigerant and in thermal communication with said first thermo-fluid liquid having said first thermo-fluid liquid temperature, wherein said thermal mass is selected from a group consisting of a reservoir of water such as a swimming pool, a geothermal system, and a cooling tower; and wherein said primary power source is selected from a group consisting of at least one passive solar panel, at least one photovoltaic solar panel, at least one fuel cell, and a combination of at least one passive solar panel with at least one fuel cell.
 4. The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP (building cooling, heating, and power) use with a thermal mass as in claim 3, further comprising: a refrigerant reversing valve allowing heat pump operation; and a diurnal and seasonal thermal load balancing system having a control module by which said low pressure absorption chiller/heat pump and said pump & valve system are automatically reconfigured for daytime and nighttime, allowing a change between a heating mode and a cooling mode depending on a user input and seasonal ambient conditions; wherein said ambient air heat exchanger is a plenum-mounted indoor heat exchanger in thermal communication with air from a residential living space, said thermal mass heat exchanger is an outdoor heat exchanger, and said control module includes a thermal mass cooling system, in thermal communication with said thermal mass, by which a flow of said first thermo-fluid liquid is cooled thereby serving to maintain stable conditions in said thermal mass through dissipation of excess thermal energy; and wherein said control module provides a cooling configuration in which a flow of first thermo-fluid liquid to the thermal mass heat exchanger is in parallel to a flow of first thermo-fluid liquid to the absorber, and a heating configuration in which the flow of first thermo-fluid liquid to the thermal mass heat exchanger is in series with the absorber whereby the thermal mass heat exchanger receives the flow of first thermo-fluid liquid preheated by the absorber; a daytime heating configuration in which the first thermo-fluid liquid is provided directly from said primary power source and provides direct heating to said plenum-mounted indoor heat exchanger; and a nighttime heating configuration in which the plenum-mounted indoor heat exchanger is heated by a heat pump configuration in which the thermal mass heat exchanger is connected in series with the absorber by a flow of first thermo-fluid liquid from the thermal mass by which the absorber preheats said flow of first thermo-fluid liquid to the thermal mass heat exchanger operating as an evaporator.
 5. The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in claim 4, further comprising a Domestic Hot Water (DHW) pre-heat exchanger which provides pre-heated water from a mains water supply.
 6. The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in claim 1, further comprising a two-step condenser system having: a primary condenser which receives a flow of refrigerant vapor from said generator, and is in thermal communication with a flow of said first thermo-fluid liquid, which in a cooling mode is in parallel to a flow of said first thermo-fluid liquid that cools said absorber; a condensate sub-cooler in thermal communication with a sub-cooler coolant, and receiving refrigerant condensate produced in said a primary condenser; and a condensate sub-cooler coolant source of said sub-cooler coolant at a sub-cooler coolant temperature, said sub-cooler coolant source being in fluid communication with said condensate sub-cooler; wherein said sub-cooler coolant temperature is lower than said first thermo-fluid liquid temperature; and wherein said low pressure ammonia-water absorption chiller/heat pump has a ratio of an internal absolute pressure within said generator to an internal absolute pressure within said absorber equal to or less than 2:1.
 7. The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in claim 6, further comprising a primary power source in thermal communication with said ammonia-water absorption chiller/heat pump and with said thermal mass.
 8. The ammonia-water absorption system for BCHP residential use with a thermal mass of claim 7, further comprising a pump & valve system in fluid communication with said absorption heat pump, with said thermal mass, with said primary power source, and with said condensate sub-cooler coolant source; wherein said thermal mass is selected from a group consisting of a reservoir of water such as a swimming pool, a geothermal system, and a cooling tower; and wherein said primary power source is selected from a group consisting of at least one passive solar panel, at least one photovoltaic solar panel, at least one fuel cell, and a combination of at least one passive solar panel with at least one fuel cell.
 9. The low pressure ammonia-water absorption chiller/heat pump system for residential BCHP use with a thermal mass as in claim 8, further comprising a diurnal and seasonal thermal load balancing system having a control module by which said low pressure absorption chiller/heat pump and said pump & valve system are automatically reconfigured for daytime and nighttime, selecting between a heating mode and a cooling mode depending on a user input and seasonal ambient conditions; wherein said control module includes a thermal mass cooling system, in thermal communication with said thermal mass, by which a flow of said first thermo-fluid liquid is cooled thereby serving to maintain stable conditions in said thermal mass through dissipation of excess thermal energy.
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 21. A hybrid double-effect sorption chiller/heat pump system; comprising at least one single effect absorption chiller stage based on a first refrigerant, and having a generator with an external heat source, an absorber, a first evaporator, a liquid-cooled primary condenser, a GAX (Generater-Absorber eXchanger), a heat recovery recuperator recovering heat from a flow of first refrigerant to the condenser and from a first solution flow out of the absorber; at least one solid adsorption chiller stage based on a second refrigerant, further comprising a housing with at least one pair of adsorber/desorber sections, each of said sections having at least one adsorber/desorber heat exchanger in thermal contact with a quantity of adsorbent material, and in second refrigerant vapor communication with at least one adsorption-stage evaporator/condenser section by way of a thermal insulation layer permeable to vapor of said second refrigerant, said adsorption-stage evaporator/condenser section having at least one evaporator/condenser heat exchanger; at least one hot thermo-fluid secondary loop having a pump and in thermal communication with said heat recovery recuperator, with said primary condenser, with said at least one adsorber/desorber heat exchanger and with said at least one evaporator/condenser heat exchanger; at least one thermal mass in thermal communication with said at least one hot thermo-fluid secondary loop; at least one chilled thermo-fluid secondary loop in thermal communication with said first evaporator and with said at least one adsorption-stage evaporator, and operating simultaneously with said at least one hot thermo-fluid secondary loop; and a DHW (domestic hot water) heat exchanger in thermal communication with said at least one hot thermo-fluid secondary loop; wherein each of said pair of adsorber/desorber sections cycles alternately between an adsorption phase and a desorption phase with one section of said pair being in an adsorption phase while the other section is in a desorption phase, and the evaporator/condenser section operates as an evaporator when it is in vapor communication with an adsorber/desorber section in an adsorption phase, but operates as a condenser when it is in vapor communication with an adsorber/desorber section in an desorption phase; and wherein said adsorber/desorber section when in an desorption phase is driven, at least in part, by heat of condensation recovered from said at least one single effect absorption chiller stage, thereby acting as a hybrid second effect of said hybrid double-effect sorption heat pump.
 22. The hybrid double-effect sorption chiller/heat pump system of claim 21; further comprising at least one photo-voltaic solar array; wherein said at least one heat recovery heat source is a flow of air having thermal contact with a dark side of at least one panel of said photo-voltaic solar array.
 23. The hybrid double-effect sorption chiller/heat pump system of claim 22; wherein said at least one external heat source is a condensing burner which burns a fuel selected from the group composed of natural gas, liquified petroleum gas (LPG, e.g. propane), and fuel oil; whereby said burner provides supplementary heat at times when the heat recovery is insufficient to drive the at least one solid adsorption chiller stage.
 24. The hybrid double-effect sorption chiller/heat pump system of claim 23; wherein said first refrigerant is water, and said adsorbent material is selected from the group consisting of silica gel and silica zeolite.
 25. The hybrid double-effect sorption chiller/heat pump system of claim 24; wherein said absorption-stage rectifier is cooled by a second flow of solution out of the absorber.
 26. A solar heat recovery-driven adsorption chiller/heat pump system; comprising at least one solar heat recovery heat source; at least one external heat source; at least one heat recovery recuperator in thermal communication with said at least one solar heat recovery heat source; at least one solid adsorption chiller stage based on a first refrigerant, further comprising a housing with at least one pair of adsorber/desorber sections, each of said sections having at least one adsorber/desorber heat exchanger in thermal contact with a quantity of adsorbent material, and in refrigerant vapor communication with at least one adsorption-stage evaporator/condenser section by way of a thermal insulation layer permeable to vapor of said first refrigerant, said adsorption-stage evaporator/condenser section having a evaporator/condenser heat exchanger; at least one hot thermo-fluid secondary loop having a pump and in thermal communication with said heat recovery recuperator, with said at least one solar heat recovery heat source, with said at least one adsorber/desorber heat exchanger and with said evaporator/condenser heat exchanger; at least one thermal mass in thermal communication with said at least one hot thermo-fluid secondary loop; at least one chilled thermo-fluid secondary loop in thermal communication with said at least one adsorption-stage evaporator, and operating simultaneously with said at least one hot thermo-fluid secondary loop; at least one fan coil in thermal communication with said at least one hot thermo-fluid secondary loop, or in the alternative with said at least one chilled thermo-fluid secondary loop for heating or cooling respectively a flow of air from a living space; and a DHW (domestic hot water) heat exchanger in thermal communication with said at least one hot thermo-fluid secondary loop; wherein each of said pair of adsorber/desorber sections cycles alternately between an adsorption phase and a desorption phase with one section of said pair being in an adsorption phase while the other section is in a desorption phase, and the evaporator/condenser section operates as an evaporator when it is in vapor communication with an adsorber/desorber section in an adsorption phase, but operates as a condenser when it is in vapor communication with an adsorber/desorber section in an desorption phase.
 27. The solar heat recovery adsorption chiller/heat pump system of claim 26; further comprising at least one photo-voltaic solar array; wherein said at least one solar heat recovery heat source is a flow of air having thermal contact with a dark side of at least one panel of said photo-voltaic solar array; whereby said at least one solid adsorption chiller stage is driven by heat recovered from the dark side of said photo-voltaic solar array.
 28. The solar heat recovery adsorption chiller/heat pump system of claim 27; wherein said at least one external heat source is an on-demand domestic hot water heater with a condensing burner which burns a fuel selected from the group composed of natural gas, liquid petroleum gas (LPG, e.g. propane), and fuel oil; whereby said burner provides supplementary heat at times when the heat recovery is insufficient to drive the at least one solid adsorption chiller stage.
 29. The solar heat recovery adsorption chiller/heat pump system of claim 28; wherein said first refrigerant is water, and said adsorbent material is selected from the group consisting of silica gel and silica zeolite. 